SUPPLEMENT.— LIOCERAS. 



XXXV 



and Quenstedt's 1 fig. 10 in pi. vii of bis ' Cephalopoden ' is regarded as the arbiter 

 of what is opalinus. 



There is, however, further trouble. The opalinus as now identified occurs at a 

 higher horizon — it lived at a later date — than what I regarded, in part, as opalinus 

 before, so that the term " opalinus beds " must be rejected, and the hemeral 

 nomenclature must be altered in accordance with the present conclusions. 



The annexed table gives the strata of the Cotteswolds and of the South Dorset 

 coast, which were deposited during four hemeras ; and it will therefore show the 

 relative dates of opalinus and of opalinoid species. 



Bate. 



Stratal succession. 



Hemerje 



Murchisonie 



Scissi 



Opaliniformis 



Aalensis 



Cotteswolds. 



Pea-grit series, with Amm. of 

 the Murchisonie type. 



Saiidy ferruginous Limestone 

 with Tmetoceras scissum and 

 Lioceras species. 



Hard ironshot Limestone cap- 

 ping the Cephalopod-bed, with 

 opalinoid species = Cypholio- 

 ceras. 



Ironshot marly stone of the 

 Cephalopod-bed, with species 

 of the aalense type. 



South Doeset Coast, 

 generalised. 



Ironshot Limestone = the "Wild 

 Bed" of Chideock Quarry, 

 with Amm. of the Murchisonie 

 type. 



Bluish -grey Limestone with 

 Tmetoceras scissum and Lio- 

 ceras species. 



Yellow sands with opalinoid 

 species = Cypholioceras. 



Yellow sands with species of 

 the aalense type. 



The genus Lioceras and its species may now be considered in detail. 



VII. Genus — Lioceras, Hyatt. 



(Type : Liocebas opalinuii, Eeineeke sp.) 



18G7. Lioceeas, Hyatt, Foss. Ceph., Bull. Mus. Coinp. Zool., p. 101 (pars). 

 1887. — This Monogr., pp. 12, 21 (pars). 



Definition. — Platyleptogyral, angustumbilicate ; subdensiseptate, subbrevi- 

 angustilobate ; laterally flexiradiate ; peripherally subanguliradiate, subacutifasti- 

 gate, parvi-nonsepti-carinate. 



History. — See the prefatory remarks, p. xxxiii. 



1 Quenstedt himself confused several species as opalinus. In the ' Jura ' he figures two forms 

 which show differences of radial curve, and in his ' Schwabisehen Amm.' he depicts not only forms 

 with differences of radial curve, but also lat- and august-umbilicate examples, all as opalinus. 



